During the past decade, microcurrent therapy has been shown to be effective in pain control. Microcurrent electrical therapy or microcurrent therapy, first coined by Mercola and Kirsch in 1995, describes a new form of electro-medical intervention using biocompatible waveforms and uses current in the microampere range, 1000 times less than that of transcutaneous electrical nerve stimulation (i.e. TENS) and below the sensation threshold.
Some of the early thinking relating to energy treatments, as shown in studies reviewed by North (9) and by Neumann (11), was that if some electricity is good perhaps more is better. This concept, however, was later challenged by investigators such as Becker and Nordenstrom, who wrote “The Body Electric” (2) and “Biological Closed Electric Circuits: Clinical, Experimental, and Theoretical Evidence for an Additional Circulatory System”(12), respectively.
Microcurrent stimulators have been used since early 1980s, but only recent technological advances in electronics and power sources have allowed more advanced devices that are wearable and portable.
Studies by Illingsworth (13) and Vodovnick (5) have found microcurrent reduces inflammation, edema and swelling, increases range of motion, strength and muscle relaxation, and accelerates wound healing. These current therapies have also been found by Stanish (6)) and Stanish and Lai (7) to be effective in soft tissue injuries, such as sprains and has also been proven useful in preventing the delayed muscle soreness that is common after heavy exercise. These current therapies have been used to control failed back syndrome as referenced by North (9) and shown by LeDoux (10) and for arthritis according to Neumann (11). There is a growing body of research showing that MCT is capable of doing more than just control pain, such as accelerating and even inducing healing. It has also been proven useful in preventing the delayed muscle soreness that is common after heavy exercise as shown by Kulig (8)
William Stanish, a physician for the Canadian Olympic Team demonstrated that implanted electrodes delivering 10-20 microamps of electrical current hastened the recovery from ruptured ligaments and tendons. Using microcurrent stimulation, Dr. Stanish shortened the normal 18 month recovery period to only 6 months, as reported in Physician and Sportsmedicine (6).
Physiological effects of MCT, which has also been called “bio-stimulation” or “bio-electric therapy” because of its ability to stimulate cellular physiology and growth was first demonstrated in a landmark study (3) by Cheng et al. in 1982. Using varying levels of electrical current on in-vitro slices of rat skin, the investigators showed up to 500% increase in ATP generation as well as increase in amino acid transport and protein synthesis in specimens treated with currents below 600 microamps, compared to that of the control group. The most significant finding of this study was specimens stimulated at levels above 1 milliamp (TENS levels) showed depressed levels of amino acid synthesis and ATP generation, often significantly lower than controls. This was strong evidence of the superiority of microcurrents over milliamp currents for stimulating cellular healing.
Becker has shown that trauma will affect the electrical potential of cells in damaged tissues. Initially, the site of an injury has much higher resistance than the surrounding tissue. Basic physics dictates that electricity will always take the path of least resistance; therefore, endogenous electrical current will travel around the site of injury. This results in decreased electrical conductance through the injured area and decreased cellular capacitance, leading to impairment of the healing process as shown by Windsor (14) in Physician and Sportsmedicine.
Pain, heat, swelling and redness are the characteristics of inflamed tissues. It has been reported that electricity flows more readily through inflammatory fluids and correct application of microcurrent to an injured site is believed to enhance the endogenous current flow, thus allowing cells in the traumatized area to regain their capacitance. A study has reported on a link between the effects of microcurrent to enhanced cellular activities such as protein synthesis and ATP generation and is believed to be the key mechanism of action for microcurrent therapy. See Cheng (3).
Microcurrent is an energy-based therapy, defined as the application of electrical current to the external parts of the body, typically on the skin, and applied as a current in a range of 20-500 microamperes. A typical microcurrent apparatus is composed of a patch and with an accompanying power supply source with positive and negative energy delivery electrodes leads attached from the power supply source s. While microcurrent is applied to external parts such as the skin, it is used for treatment of pain in both muscle and joint tissue and may be applied in various configurations to the elbows, knees, back, shoulder or neck. Generally, microcurrent is supplied through a device and is differentiated from other electrotherapy devices in that the amount of current which is supplied is less than the amount used in transcutaneous electrical nerve stimulation (i.e. TENS).
TENS devices are known for delivering electromagnetic stimulation as described in U.S. Pat. No. 4,121,594; “Transcutaneous Electrical Nerve Stimulator”, Miller et. al; and U.S. Pat. No. 5,423,874; “Patch for Applying Pain Reducing Energy to the Body” D'Alerta et. al. A microcurrent therapy device can be defined as one which delivers a DC current of less than one milliampere, typically in the range of 20-500 microamperes; whereas TENS devices deliver DC current in a range greater than 1 milliampere; typically at 5 to 20 milliamperes. Devices for use in the application of therapeutic microcurrent is described in U.S. Pat. No. 5,354,321.
Microcurrent devices are generally applied for a long period of time, which includes wearing the device for a time longer than that used for TENS devices. In addition, one major characteristic inherent in microcurrent devices is that the current which is supplied is transmitted below the sensory threshold of the user, and in turn, is not “felt” immediately upon application of the device. Pain relief is achieved over an extended period of time while wearing the device and it is further believed to have longer term effects beyond stimulation.
Since the microcurrent energy is not sensed by the user, it is advantageous to let the user know that the device is working and delivering the appropriate therapeutic dose of microcurrent through the device. A solution to this has been proposed in U.S. Pat. No. 6,408,211; “Microcurrent Therapy Device” is the addition of a visual indicator, such as LED, to the surface of the device, which indicates to the user that the device is on and working. One issue with this approach is that most users do not associate LED indication in conjunction with pain relief or energy delivery, and in essence does not act to deliver any additional cue to the user that the device is actually functioning in a temporary pain relieving capacity. In addition, the user must remember to periodically examine the device to see whether or not the LED is on. The requirement for a visual check could be very difficult if the site of pain is out of the visual capacity of the user (i.e. low back pain) and when the device is worn under the user's clothing. Additionally, a further shortcoming is that the LED signal is not detectable to a user while sleeping. Further, the proposed solution does not provide a signal of dysfunction. For example, if a user is moving or if the friction from clothing disconnects the device, contact uniformity is disrupted, and there is no signal to communicate the disruption to the user.
U.S. Pat. No. 6,606,519 describes a microcurrent therapy device that includes various components, including a coin battery and conductive pads, in a stack configuration.
Published U.S. Patent Application 20040138712 describes a combination stimulating and exothermic heating device and method of use. This application describes types of eletrostimulation such as TENS which actually provides a therapeutic treatment to the user in combination with an exothermic heating therapeutic component, which is a type of heat which is difficult to control and deliver in a precise or timed manner.
Published PCT Application WO 2005/119610 describes an electrocommunication unit which is used for delivering a series of electrical pulses to the skin to serve as a reminder or wake-up device.
U.S. Pat. No. 6,175,763 describes an electrotransport system for delivering active drugs through the skin and for delivering a tactile signal to the skin of a patient. The system includes a sensor connected to the system for sensing an event or condition associated with the operation of the system. The method includes monitoring a condition or event associated with the operation of the system and generating a tactile signal, which signal can be felt by the patient wearing the system, when the condition or event occurs.
The following references and patents/patent applications are discussed above are incorporated herein by reference:
1. Mercola, J. M., Kirsch, D. L. (1995). The basis for microcurrent electrical therapy in conventional medical practice. Journal of Advancement in Medicine, 8 (2), 107-120.
2. Becker R O. The Body Electric. New York: William Morrow and Co., 1985.
3. Cheng N., et al. The effects of electric currents on ATP generation, protein synthesis and membrane transport in rat skin. Clin. Orthop. 1982; 171:264-272.
4. Reich J D and Tarjan P P. Electrical stimulation of skin. Int. J. Derm. 1990; 29:395-400.
5. Vodovnik L and Karba R. Treatment of chronic wounds by means of electric and electromagnetic fields. A literature review. Med Biol Engineer Comput. 1992; 30:257-266.
6. Stanish W D, et al. The use of electricity in ligament and tendon repair. Physician and Sportsmedicine. 1985; 13:109-116.
7. Stanish W D and Lai A. New concepts of rehabilitation following anterior cruciate reconstruction. Clin. Sports Med. 1993; January; 12(1):25-58.
8. Kulig K, et al. The effect of microcurrent stimulation on CPK and delayed onset muscle soreness. Physical Therapy. 1991; 71:6(suppl).
9. North R B, et al. Spinal cord stimulation for chronic, intractable pain: experience over two decades. Neurosurgery. 1998; 32:384-395.
10. LeDoux M S and Langford K H. Spinal cord stimulation for the failed back syndrome. Spine. 1993; 18:191-194.
11. Neumann V. Electrotherapy. Br J Rheumatol. 1993; 32:1-3.
12. Nordenstrom, B. Biological Closed Electric Circuits: Clinical, Experimental, and Theoretical Evidence for an Additional Circulatory System. Nordic medical Publications. Uppsala. 1983.
13. Illingsworth C M and Barker A T. Measurements of electrical currents emerging during the regeneration of amputated fingertips in children. Clinical Phys. Physiol. Meas. 1980; 1:87-89.
14. Windsor R E, et al. Electrical Stimulation in Clinical Practice. Physician & Sportsmedicine. 1993; 21:85-93.